<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .outer{
            border: 1px solid red;
            overflow: hidden;
            width: 150px;
            height: 200px;
        }
        .inner{
            width: 300px;
            height: 300px;
            padding: 10px;
            border: 20px solid seagreen;
            background: green;
        }
    </style>
</head>
<body>
    <div class="outer">
        <div class="inner">

        </div>
    </div>
    <script>
        var _clientw=document.querySelector('.inner').clientWidth;
        var _clienth=document.querySelector('.inner').clientHeight;
        var _offsetw=document.querySelector('.inner').offsetWidth;
        var _offseth=document.querySelector('.inner').offsetHeight;
        console.log(_clientw,_clienth)
        console.log(_offsetw,_offseth)
    </script>
</body>
</html>